Studying Child Development:
∙ Research in Child Development
o How do we learn about child development?
– Collect data at multiple ages, analyze it, and interpret the results o Data Collection
– Ask the child
– Ask others about the child
– Assess the child
– Observe the child
– Naturalistic observation: In naturalistic observation, children are observed as they behave spontaneously in a reallife situation.
– Structured observation: ice cream cone challenge; In structured observation, the researcher creates a setting likely to elicit the
behavior of interest.
o Developmental Research Designs
– Longitudinal design
∙ Advantages: Study the actual development of individual
∙ Disadvantages: Timeconsuming; Expensive; Subject drop
out; Repeated testing may influence behavior; Cohort
– Crosssectional design
∙ Advantages: Can be done quickly; More likely to have
large sample sizes
∙ Disadvantages: Compares different children; Makes
assumptions about development; Cohort effects
– Longitudinalsequential design We also discuss several other topics like What are the 2 types of speakers tannen identifies?
If you want to learn more check out Why is attractiveness so important?
∙ Advantages: Can examine changes in the same individual
as well as between groups; Can identify and statistically
control cohort effects and practice effects
∙ Disadvantages: Timeconsuming; Complex to conduct and
o Cohort Effects: the phenomenon whereby a group of people are influenced by historical forces or events unique to the time and/or place in which they live. Cohort effects limit the generalizability of the findings.
∙ Interpretation of Results
o Experimental Method:
Elements of an experiment
– Random sample/random assignment
– Experimental group
– Control group
– Independent variable
– Dependent variable
The effect of a new drug on problem behaviors in elementary school children diagnosed with ADHD
- Experimental group?
Children who receive the drug
- Control group?
Children who receive placebo
- Independent variable
Use of drug (yes or no) We also discuss several other topics like What is atherosclerosis?
- Dependent variable
Problem behaviors as rated by teacher response to the
Teacher should not know which children are receiving the drug
Advantages: Can reveal cause and effect
Disadvantages: Many questions cannot be addressed using the
experimental method We also discuss several other topics like What is financial leverage give formula?
o Correlational Method:
Correlation coefficient(r): the measure of the relation between two variables
- Positive correlation
- Negative correlation
Advantages: Easy to design and analyze; Allows for the measurement of associations that cannot be manipulated in an experiment
Disadvantages: Correlation does not indicate causation! Direction of effect; Third factor; Coincidence– Friends Example
Headlines and News Reports
- Eating chicken on the bone makes kids more aggressive.
- Television causes diabetes.
- The MMR vaccine causes autism.
- Violent TV makes kids violent adults.
- Classical music makes babies smarter.
- Spanking lowers intelligence.
Why is accurate data interpretation important?
- Financial impact (retest unethical costs a lot of money)
- Health impact (parents may believes fake science, and don’t vaccine their babies)
Influences on development: We also discuss several other topics like What physical and motor developments are seen in 12- to 18-monthold children?
∙ Genetic Influences
o Heredity: the biological transmission of traits and
characteristics through genes
- Each egg and sperm cell contains 23 chromosomes, tiny structures in the nucleus that contain genetic
- The first 22 pairs of chromosomes are called autosomes; and the chromosomes in each pair are about the same size.
o Sex Determination:
- Sex chromosomes: 46 chromosomes; 23rd pair determines the sex of the child; An egg always contains an X 23rd chromosome, but a sperm contains either an X or a Y. When an Xcarrying sperm fertilizes the egg, the 23rd pair is XX and the result is a girl. When a Ycarrying sperm fertilizes the egg, the 23rd pair is XY and the result is a boy.
- Notice that no disorders consist solely of Y chromosomes. The presence of an X chromosome appears to be necessary for life. -
o Genes We also discuss several other topics like How do we look to shareholders?
- Each chromosome actually consists of one molecule of deoxyribonucleic acid; DNA for short.
- Each group of nucleotide bases that provides a specific set of biochemical instructions is a gene.
- The complete set of genes makes up a person’s heredity and is known as the person’s genotype.
o Single Gene Inheritance:
- Genetic instructions, in conjunction with environmental influences, produce a phenotype, an individual’s physical, behavioral, and psychological features. Sometimes the alleles in a pair of chromosomes are the same, which makes them homozygous. Sometimes the alleles differ, which makes them heterozygous.
- When a person is heterozygous, the process is more complex. Often one allele is dominant, which means that its chemical instructions are followed whereas instructions of the other, the recessive allele, are ignored.
- Individuals with one dominant and one recessive allele have sickle cell trait: In most situations they have no problems, but when they are seriously short of oxygen they suffer a temporary, relatively mild form of the disease.
o Alleles: versions of a gene (e.g., dominant or recessive) that act across pairs of chromosomes; Genes come in different forms that are known as alleles.
Sometimes one allele does not dominate another completely, a situation known as incomplete
Inherited Disorders Sicklecell disease is one of many disorders that are homozygous recessive—triggered when a child inherits
recessive alleles from both parents.
o Polygenic Inheritance: Phenotypes distributed like this often reflect the combined activity of many separate genes, a pattern known as polygenic inheritance. when coupled with many intermediate cases, produce the familiar bell-shaped distribution that characterizes many behavioral and psychological traits.
o Chromosome Abnormalities
Number: Down syndrome, a genetic disorder that is caused by an extra 21st chromosome and that
results in intellectual disability. And it is typified by
development that is slower than normal
Structure: DNA issues. disorders are inherited.
Phenylketonuria (PKU): an amino acid, accumulates in the body and damages the nervous system,
causing mental retardation. Huntington’s disease, a fatal disease characterized by progressive
degeneration of the nervous system. disease PKU,
which can be expressed only when children inherit a recessive gene on chromosome 12 from both parents (i.e., the child is homozygous recessive).
∙ Environmental Influences
o Children live and grow within a multifaceted context of family, society, and culture.
o Ecological Systems Theory: focuses on the complex interplay of factors that influence development and highlights the key concepts covered in this course.
- Child is at the center of the system.
- Microsystem: the child’s daytoday setting: the microsystem consists of the people and objects in an individual’s immediate
environment. These are the people closest to a child, such as
parents or siblings. Some children have more than one
microsystem; for example, a young child might have the
microsystems of the family and of the day care setting. As you
can imagine, microsystems strongly influence development.
- Mesosystem: the connections among microsystem influences: Microsystems themselves are connected to create the mesosystem. The mesosystem represents the fact that what happens in one
microsystem is likely to influence what happens in others.
- Exosystem: aspects of the environment that indirectly influence the child. Example: a mother’s work environment is part of her child’s exosystem, because she may pay more attention to her child when
her work is going well and less attention when she’s under a great
deal of workrelated stress.
- Macrosystem: the characteristics of the culture or subculture in
which the child lives: The broadest environmental context is the
macrosystem, the subcultures and cultures in which the
microsystem, mesosystem, and exosystem are embedded.
o Chronosystem: these systems all change over time, This dimension reminds us that microsystem, mesosystem, exosystem, and macrosystem are not static but are constantly in flux. For example, the child’s
microsystem changes when an older sister leaves home to attend college and the child’s exosystem changes when a mother leaves an easy but low paying job for a more challenging but higherpaying job.
∙ Gene X Environment Interactions
o Child development cannot be explained by any single concept such as genes, parenting, peer pressure, television, or culture. In more general terms, a genotype is expressed differently (no disease) when it is exposed to a different environment (one lacking phenylalanine).
o Genes and the environment interact in complex ways to influence development
o Genes influence the environment. “nature” can help determine the kind of “nurturing” that a child receives
Nichepicking: is the process of deliberately seeking environments that fit one’s heredity. Through nichepicking, the environment
amplifies genetic differences
o Specific environments affect only individuals with particular genetic predispositions. The environmental influences, the environmental forces that make siblings different from one another. Although environmental forces are important, they usually affect each child in a unique way, which makes siblings differ. each child in a family experiences a unique
environment.—nonshared environment influences
o Genes can determine a range for developmental outcomes. Environment influences development within that range.
o Epigenesis: environmental influences determine which genes are expressed (“turned on” or “turned off”). This continuous interplay between genes and multiple levels of the environment (from cells to culture) that drives development is known as epigenesis.
∙ Behavioral Genetics
o Behavioral Genetics: the study of how genes and the environment interact to influence traits and behaviors
o Heritability coefficient: the extent to which the differences among people reflect heredity (genetic influence) behavioral
geneticists often use correlations from twin and adoption studies to calculate
– Values range from 0.00 to 1.00 IQ is 0.5
o Determining Heritability: Determining the impact of heredity on behavioral and psychological traits is the aim of behavioral genetics. Twin studies: Monozygotic twins more alike than dizygotic twins ∙ Monozygotic twins: identical
∙ Dizygotic twins: fraternal
Adoption studies: Children more like biological parents than
∙ Biological parents & siblings
∙ Adoptive parents & siblings
DNA marker analyses: researchers can obtain DNA by gathering cheek cells from inside a child’s mouth. A solution containing the
DNA is placed on a microarray. Every match between the child’s
DNA and the known sequences is recorded, creating a profile of
the child’s genotype. Researchers then look to see if the genotype
is associated with behavior phenotypes. For example, in one study
10 alleles were linked with children’s skill in mathematics
∙ Stages of Prenatal Development:
o Period of the Zygote (Fertilization – 2 weeks): It ends when the fertilized egg, called a zygote, implants itself in the wall of the uterus.
∙ Path to he uterus:
∙ Conception: Fertilization takes place in the fallopian tube ∙ Cell Replication: about 36 hours 2 cells; 48 hours 4 cells; 4 days 100cells
∙ Differentiation:the process by which cells specialize and begin to take on different roles
Trophoblast: become structures that support, nourish, and the developing organism.
Embryoblast: eventually develops into the baby
The layer of cells closest to the uterus becomes the
placenta, a structure for exchanging nutrients and wastes
between the mother and the developing organism.
∙ Implantation: By the end of the first week, the zygote reaches the uterus. The next step is implantation: The blastocyst burrows into the uterine wall and establishes connections with the mother’s blood.
o Period of the Embryo (2 – 8 weeks): After the blastocyst is completely embedded in the uterine wall, it is called an embryo
∙ 2 weeks: Three layers form in Embryo:
The outer layer or ectoderm will
become hair, the outer layer of skin,
and the nervous system
The middle layer or mesoderm will form muscles, bones, and the circulatory system
The inner layer or endoderm will form the digestive system and the lungs.
∙ 4 weeks: the fertilized egg is about 2 millimeters long and resembles a salamander.
∙ 8 weeks : near the end of the period of the embryo, the fertilized egg is obviously recognizable as a baby to-be. Baby is one inch long
The embryo’s environment:
∙ Amniotic sac: a fluidfilled sac which surrounds and protects the embryo and cushions the embryo and maintains a constant
∙ Placenta: a mass of tissue that supplies oxygen and nutrients to the embryo and carries away waste products
∙ Umbilical cord: a cord containing blood vessels that connects the embryo to the placenta; In the placenta, the blood vessels from the umbilical cord run close to the mother’s blood vessels but aren’t actually connected to them. Instead, the blood flows through villi, fingerlike projections from the umbilical blood vessels; Villi lie close to the mother’s blood vessels and allow nutrients, oxygen, vitamins, and waste products to be exchanged between mother and embryo.
o Period of the Fetus (8 weeks – birth): During this period, the babytobe becomes much larger and its bodily systems begin to work. About 4 months, the fetus weighs roughly 48 ounces enough fir the mother to feel it move. ∙ Growth
∙ Fine Tuning
∙ Age of viability: At 22 to 28 weeks after conception, the fetus has achieved the age of viability, meaning that it has a chance of surviving if born prematurely.
∙ Teratogens: any substance that can cause damage during the prenatal period
Some of these diseases pass from the mother through the placenta to attack the embryo or fetus directly. Other diseases attack at birth: The virus is present in the lining of the birth canal, and the baby is infected during the birth process.
Alcohol: Fetal alcohol spectrum disorder, cognitive
deficits, retarded growth; Pregnant women who regularly
consume quantities of alcoholic beverages may give birth
to babies with fetal alcohol spectrum disorder (FASD). The
most extreme form, fetal alcohol syndrome (FAS), is most
likely among pregnant women who are heavy drinkers;
When women drink moderately throughout pregnancy,
their children are often afflicted with partial fetal alcohol
Cigarettes: nicotine, Retarded growth, possible cognitive impairments; The nicotine in cigarette smoke constricts
blood vessels and thus reduces the oxygen and nutrients
that can reach the fetus through the placenta. Therefore,
pregnant women who smoke are more likely to miscarry
(abort the fetus spontaneously) and to bear children who
are smaller than average at birth
Environmental agents: Environmental teratogens like those shown are treacherous because people are often unaware of
their presence in the environment.
o Chemicals: The amount of PCBs(used in paints) in
a typical contaminated fish does not affect adults,
but when pregnant women ate large numbers of
PCBcontaminated fish, their children’s cognitive
skills and reading achievement were impaired
o Radiation: Xrays: Retarded growth, leukemia,
∙ Teratogens: Determinants of Damage
Genetic vulnerability: The impact of a teratogen depends on the genotype of the organism. Using same doses drug, some women gave birth to babies with normal limbs, but others did not. So, heredity makes some individuals more susceptible than others to a teratogen.
Amount of exposure: The impact of teratogens depends on the dose. More exposure, more harmful.
Timing of exposure: The impact of teratogens changes over the course of prenatal development. The timing of exposure to a teratogen is critical; During the period of the zygote, exposure to teratogens usually causes the fertilized egg to be aborted spontaneously. During the embryonic period, exposure produces major defects in body structure. During the fetal period, exposure to teratogens either produces minor defects in body structure or causes body systems to function improperly.
o Hand development;
o Thalidomide: drug to help them sleep. Thalidomide was a powerful teratogen, that many produced
children with deformed limbs.
after 5weeks, no
impact to baby
According to the following form:
o No data in period of zygote, because, no placenta, baby don’t connect to Mom.
o Baby is most vulnerable in Embryo
o Brain is vulnerable in a long period
∙ Maternal Health
Many health conditions: can affect pregnancy; Depression;
Asthma; Obesity; Diabetes; Heart Conditions; Thyroid
Disease; Epilepsy; Infections
Medication: Pregnant women should consult a doctor
before taking ANY medication; Pregnant women should
also consult a doctor before stopping or changing
Nutrition: folic acid, one of the B vitamins, is important for
the nervous system to develop properly. When mothers do
not consume adequate amounts of folic acid, their babies
are at risk for spina bifida, a disorder in which the embryo’s
neural tube does not close properly during the first month
Herbs: is not safe enough, is not regulated by FDA, maybe
has potential issue.
∙ What Should Women Do?
Adopt a healthy lifestyle.
Achieve a healthy weight.
Take a multivitamin that contains folic acid daily.
Get a prepregnancy health checkup.
When pregnant, attend all prenatal visits
∙ What Should Men Do?
Learn about pregnancy.
Adopt a healthy lifestyle.
Help create a healthy environment.
∙ Procedures: the baby is covered with vernix and is bowlegged; his head is distorted from the journey down the birth canal.
o Nose and mouth are cleared
o Umbilical cord is cut
o Preventative medical treatments are conducted
o Apgar Test – used to evaluated the newborn baby’s condition and determine if a baby is healthy and adjusting to life outside the uterus.1 and 5 minutes after birth: Heart rate (100 beats); Respiration (strong breathing and crying); Muscle tone; Color; Reflex irritability (see baby’s response)
o Newborn screening: could discover PKU
o Head: Shape; Soft spot, the gap is impotant, when is delivered form mom’s body, and the brain grow up rapidly
o Face: birth marker due to too much pigment in blood vessal. o Skin: mom’s hormone change
o Umbilical Cord
o Eat 812 times per day
o Need 812 diaper changes per day
o Sleep 1618 hours per day:
newborns sleep in naps taken round the clock. Newborns typically go through a cycle of wakefulness and sleep about every 4 hours. That is, they will be awake for about an hour, sleep for 3 hours, then start the cycle anew.
REM: baby move eyes arms and legs/ nonREM: Breathing, heart rate and brain activity are steady.
o Awake and alert enough to explore their environment 23 hours per day o Cry 13 hours per day:
A basic cry starts softly, then gradually becomes more intense and usually occurs when a baby is hungry or tired; a mad cry is a more
intense version of a basic cry; and a pain cry begins with a sudden, long burst of crying, followed by a long pause and gasping.
For soothing baby: lift or rock baby, sing lullabies, pack back, give a pacifier, swaddling (wrapped tightly in a blanket)
∙ Reflexes: unlearned, automatic responses to a particular form of stimulation; Reflexes indicate whether the newborn’s nervous system is working properly
o Rooting reflex: Rooting and sucking ensure that the newborn is ready to begin a new diet of life sustaining milk
o Sucking reflex
o Grasping reflex
o Stepping reflex: the stepping reflex looks like a precursor to walking; serve as the foundation for larger, voluntary patterns of motor activity
o Moro reflex
o Babinski reflex
∙ Adverse outcomes:
o Every week in the US 78,054 babies are born.Of these…
8,985 are premature
5,904 are low birth weight
5,854 have one or more birth defects
538 die before their first birthday
o Premature Delivery: Child born 3 or more weeks prior to full term; babies born at 30 weeks gestation have a greater than 90% survival rate in the US o Low Birth Weight:
Normal Birth Weight – ≥5.5 lbs (2500g)
Low Birth Weight – >3.3 (1500g) and <5.5 lbs (2500g)
Very Low Birth Weight – <3.3 lbs (1500g)
The heaviest baby is 15 lbs in China, the weeks decide the premature
o SmallforDate: birth weight is lower than the 10th percentile for the number of weeks of pregnancy
o Birth Defects: abnormality in structure, function, or metabolism present at birth that results in physical or mental disability, or is fatal
– Approximately 6% of children have a major structural birth defect that is identified by age 5.
o Sudden Infant Death Syndrome (SIDS): the sudden and unexplained death of a seemingly healthy infant; SIDS more often occurred when infants slept on their stomachs; babies are more vulnerable premature and their parents smoke. Two months baby is most risky
Risk reduction: Campaigns: “back to sleep” & “safe to sleep”(2012, new) educate parents about the dangers of SIDS and the importance of putting babies to sleep on their backs.
Safe Sleep for Your Baby:
1. Baby sleeps in crib
2.Baby sleeps on back
3.Nothing in sleep area
4. Baby’s face uncovered
5. No smoking around baby
6. Do not overhear or overdress
7. Firm mattress tightfitting sheet
- The green line is the percentage of putting baby sleep on the back
- Issue of back sleep: babies learned crawl later or don’t crawl, if
sleep on the back, cause they cannot build limb’s strength.
- 1993 the campaign started
Nutrition and Health:
World Health Organization – 24 months
American Academy of Pediatrics – 12 months
o Prevalence in the US
74% of children were ever breastfed
43% are breastfed at 6 months—teeth come out
23% are breastfed at 12 months
o Benefits: strength bonding with mom, reduce breast cancer rate, fewer infection; a mother’s breast milk
contains antibodies that kill bacteria and viruses.
breast-fed babies are less prone to diarrhea and
constipation; eases the transition to solid foods.
o Concerns: work
Foods: started 46 months
o Baby Cereal
o Strained Vegetables and Fruits
o Strained Meats
o Finely Chopped Finger Foods
∙ Caloric Needs:
∙ Getting Children to Eat a Healthy Diet
o Teach Children About Nutrition
Food Guide Pyramid: a balt
anced diet that includes all five major food groups (grains,
vegetables, fruits, milk, and meat and beans). A healthy diet
also avoids too much sugar and, especially, too much fat.
Vegetarian and Vegan Food Pyramids
USDA Choose My Plate Campaign
∙ GO Foods – eat almost anytime
∙ SLOW Foods – eat sometimes
∙ WHOA Foods – eat only onceinawhile
o Serve Healthy Foods
Percentage of infants and toddlers consuming at least once in a
Help From Food Companies
∙ Fortified foods
∙ Fat free/low fat/sugar free alternatives
∙ Fun packaging
When All Else Fails…
∙ Get creative
∙ Name it
∙ Hidden ingredients
∙ Body Mass Index (BMI)
o – BMI < 18.5
o Normal Weight
o – BMI 18.524.9
o – BMI 2529.9
o – BMI ≥ 30
∙ Obesity: based on BMI
o Prevalence in Adults (US); increasing trends
o Prevalence in Children: causes: 1. Heredity—Obesity runs in families, showing that genes contribute, perhaps by causing some people to
overeat, to be sedentary, or to be less able to convert fat to fuel. 2.
Parents—Many parents urge children to “clean their plates” even when the children are no longer hungry and other parents routinely use food to comfort children who are upset; 3. Sedentary lifestyle 4. Too little sleep
o Changing times
Kids sleep one hour less than 15 years ago
o Consequences: health problem, low selfesteem
o Treatment: medication; change family style
∙ Body Image:
o What does the ideal woman look like?
o What does the ideal man look like?
o What influences your opinion of what is an ideal body? – Dove campaign video
o Unrealistic goals can lead to unhealthy behaviors.
Eating disorders: Anorexia and bulimia
o Be good to your body!
One way to prevent teenage girls from developing eating
disorders is help them see faults in the thin female body
that is often idealized in the media. Teens who participate
in activities critiquing this ideal are less prone to eating